Electric switch



H. 'r. O LSON I ELECTRIC SWITCH Filed 001;. 7, .1957

Harald I]? '023072.

Patented Feb. 18, 1941 PATENT OFFICE v ELECTRIC SWITCH Harold '1. Olson, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a corporation of Delaware Application October 7, 1937, Serial No. 167,755

1 Claim.

This invention relates to liquid flow switches and more particularly to mercury switches.

An object of this invention is to provide a liquid flow switch which in one operative position 5 will complete a first circuit, and when moved towardv another operative position will complete a second circuit before breaking the first circuit, but when moved back toward its first position will break the second circuit before re-making 10 thefirst circuit.

Other objects and advantages will become apparent to those skilled in the art upon reference to the accompanying specification, claim and drawing. In the drawing;

Figure 1 shows a cross sectional embodiment of the illustrated form of the invention in which one of the circuits is closed;

Figure 2 is a sectional view of the switch shown in Figure 1 in a position in which both circuits are closed;

Figure 3 is a sectional view of the switcl) in which the second circuit is closed, and

Figure 4 shows the switch in open circuit position.

An envelope Iii of glass or other insulating material substantially tubular in shape has a generally straight lower internal surface or floor If and the conventional sealing-oil tip I2.

30 The lower surface ll of the envelope I is indented at I3 forming a raised portion it somewhat nearer one end of the tube than the other. Electrodes l5 and I6 extend within the tube to a point close to the lower surface It and between the raised portion I4 and the end of the tube to which raised portion i4 is closest. Electrodes l1 and I8 are located in the opposite end of the envelope, and likewise extend to a point adjacent the lower internal surface It. The electrodes 40 are suitably sealed into the envelope Ill as at I9, 20, 2| and 22. Electrodes'li and I1 are joined together exteriorly of the envelope as at 23. A globule of mercury 24 lies within theenvelope for the purpose of making contact with the various electrodes. f

The operation of the switch will be apparent from the various operative positions shown in Figures 1 through 4. In Figure 1 the mercury 24 is shown bridging electrodes i5 and IS. The 50 amount of mercury and position of the raised portion l4 are so proportioned that in this position of the tube all the mercury will lie between the raised portion and the end of the envelope.

55 As the envelope is tipped clockwise from the position shown in Figure 1 to a position slightly past horizontal, the mercury 24 will divide into two parts, 24a and 2th, as shown in Figure 2. This division of the mercury is caused by the raised portion I4 which is sufllciently high to re- 5 shown in Figure 2 will dislodge the portion of merc'ury 24a and it will run down the envelope to become reunited with the rest of the mercury as shown in Figure 3. Here only electrodes ll and it are bridged.

Tipping the envelope in a counter-clockwise direction from theposition shown in Figure 3 to a point slightly past horizontal will cause the mercury 24 to leave-electrodes l1 and I8 and run down the envelope until the raised portion I4 is reached, as shown in Figure 4. Here neither circuit is completed. Continued counterclockwise tipping of the envelope from the'posltion shown in Figure 4 will return the mercury to the position shown in Figure 1 in which electrodes l5 and it are bridged by the mercury.

Thus it will be seen that a single-pole doublethrow switch is provided, in which the two circuits overlap in one switching operation but not in the reverse switching operation. It will be understood that other arrangements of the various parts and other materials could be usedto accomplish the same result, and it is desired that the scope of this patent be limited only by the appended claim and prior art.

I claim as my invention: 40 In an electrical switching mechanism, in combination... a straight floored container having first and second ends tiltable to a first position in which the first end is lower and to a second position in which the second end is lower, elec- 45,

trodes in the first end for controlling a first circuit, electrodes in the second end for controlling 'a second circuit, a body of mercury for bridging the electrodes in the first end when the container is in the first position and for bridging the electrodes in the second end when the container is in the second position, and an obstruction in the first end of the container of such proportions that on tilting the container from the second posi-- tion to a position in which there is a slight grathe container to bridge the electrodes in the second end and the second portion being restrained from unbridging the electrodes in the first end of the container by the obstruction until the first portion has bridged the electrodes in the 6 second end.

HAROLD T. OLSON. 

